/**
  * Preserve the outcomes variables set in the "rdfOutcomeMap" config
  * This is required to prevent those special outcomes from being reset before every outcome processing
  *
  * @param AssessmentTestSession $session
  * @throws common_ext_ExtensionException
  */
 public static function preserveOutcomes(AssessmentTestSession $session)
 {
     //preserve the special outcomes defined in the rdfOutcomeMap config
     $rdfOutcomeMap = \common_ext_ExtensionsManager::singleton()->getExtensionById('taoQtiTest')->getConfig('rdfOutcomeMap');
     if (is_array($rdfOutcomeMap) === true) {
         $session->setPreservedOutcomeVariables(array_keys($rdfOutcomeMap));
     }
 }